Brexiters will find many contentious clauses difficult to stomach within the 585-page draft document

The 585-page draft withdrawal agreement negotiated between the European Union and the United Kingdom contains several highly contentious points that supporters of Brexit in particular will find hard to stomach. Here are some of the points that may cause problems for the prime minister, Theresa May, in parliament:

Irish border backstop

The draft Brexit agreement says both parties will “use their best endeavours” to have a future trade agreement concluded six months before the end of the transition period in December 2020, but that if this is not the case the EU and the UK could “jointly extend the transition period” for an unspecified period.

Otherwise the backstop solution for Ireland and Northern Ireland aimed at preventing a hard border would come into force. The backstop, consisting of “a single customs territory between the Union and the United Kingdom”, will apply from the end of the transition period “unless and until … a subsequent agreement becomes applicable”.

The single customs territory would cover all goods except fishery products, the agreement says, and will “include the corresponding level playing field commitments and appropriate enforcement mechanisms to ensure fair competition between the EU27 and the UK”.

There would necessarily be extra non-customs checks on some types of goods passing between Northern Ireland and the rest of the UK, which will not please the Democratic Unionist party who have consistently opposed any kind of differential treatment for Northern Ireland.

On exiting the backstop, the agreement says that if “either side considers the the backstop is no longer necessary, it can notify the other” setting out its reasons. A joint committee must then meet within six months, and both sides must agree jointly to end the backstop.

This part of the agreement would be difficult for Brexiters to swallow. They have consistently argued that Britain must be able to exit any all-UK customs union as and when it wants to be able to pursue free-trade deals around the world.

Level playing field

The agreement says that under the backstop arrangement the UK must observe “level playing field” commitments on competition and state aid, as well as employment and environment standards and tax. These measures are intended to ensure that UK businesses are not able to undercut EU industry.

Brussels has demanded “dynamic alignment”, which would oblige the UK parliament to simply cut and paste EU regulations as they are issued after Brexit. Britain must also transfer three EU tax directives into law – on the exchange of tax information, reporting on investment firms and the EU’s code of conduct on taxation.

“Non-regression clauses” will also prevent the UK from bringing in lower standards on social, environmental and labour regulations such as working hours.

Many of these requirements would also be anathema to Conservative Brexiters, for whom leaving the EU represented an opportunity to head towards a low-tax, light-regulation economy such as that seen in Singapore.